[Wasm Exceptions] Fix cfg-traversal on linking the basic block after a call

src/cfg/cfg-traversal.h

@@ -267,7 +267,8 @@ struct CFGWalker : public ControlFlowWalker<SubType, VisitorType> {
     doEndThrowingInst(self, currp);
     if (!self->unwindCatchStack.empty()) {
       // exception not thrown. link to the continuation BB
-      self->link(self->currBasicBlock, self->startBasicBlock());
+      auto* last = self->currBasicBlock;
+      self->link(last, self->startBasicBlock());
     }
   }
 
@@ -477,7 +478,8 @@ struct CFGWalker : public ControlFlowWalker<SubType, VisitorType> {
     generateDebugIds();
     for (auto& block : basicBlocks) {
       assert(debugIds.count(block.get()) > 0);
-      std::cout << "  block " << debugIds[block.get()] << ":\n";
+      std::cout << "  block " << debugIds[block.get()] << " (" << block.get()
+                << "):\n";
       block->contents.dump(static_cast<SubType*>(this)->getFunction());
       for (auto& in : block->in) {
         assert(debugIds.count(in) > 0);

test/passes/coalesce-locals_all-features.txt

@@ -0,0 +1,21 @@
+(module
+ (type $none_=>_i32 (func (result i32)))
+ (type $i32_=>_i32 (func (param i32) (result i32)))
+ (export "foo" (func $1))
+ (func $bar (result i32)
+  (i32.const 1984)
+ )
+ (func $1 (param $0 i32) (result i32)
+  (try $try
+   (do
+    (local.set $0
+     (call $bar)
+    )
+   )
+   (catch_all
+    (unreachable)
+   )
+  )
+  (local.get $0)
+ )
+)

test/passes/coalesce-locals_all-features.wast

@@ -0,0 +1,19 @@
+(module
+ (func $bar (result i32)
+  (i32.const 1984)
+ )
+ (func "foo" (param $0 i32) (result i32)
+  (local $1 i32)
+  (try
+   (do
+    (local.set $1
+     (call $bar) ;; the call may or may not throw, so we may reach the get of $1
+    )
+   )
+   (catch_all
+    (unreachable)
+   )
+  )
+  (local.get $1)
+ )
+)